Grant didn’t go in much for doctrine, but he brought a relentlessly aggressive approach to warfare. He always favored activity and forward movement to standing still. Even in victory, he would be frustrated by subordinates’ failure to pursue the retreating enemy.

In his memoirs, he records an incident that reveals his philosophy. In 1863, Union General William Rosecrans refused an order to advance to meet an enemy force while Grant was laying siege to Vicksburg, the key to controlling the Mississippi River, because Rosecrans claimed that doing so would violate the “military maxim ‘not to fight two decisive battles at the same time.’” Grant was singularly unimpressed: “If true,” he observes, “the maxim was not applicable in this case. It would be bad to be defeated in two decisive battles fought the same day, but it would not be bad to win them.”

When, in the summer of 1864, Grant informed the cautious Halleck, back in Washington, of his refusal to disengage Lee and withdraw troops to quell draft resistance in the North, Lincoln responded in language that encapsulated Grant’s tenacious approach: “I have seen your despatch expressing your unwillingness to break your hold where you are. Neither am I willing. Hold on with a bull-dog gripe [sic], and chew & choke, as much as possible.”

Sherman told his fellow officer James Harrison Wilson, “I am a damned sight smarter man than Grant; I know a great deal more about war, military history, strategy, and grand tactics than he does; I know more about organization, supply, and administration and about everything else than he does; but I’ll tell you where he beats me and where he beats the world. He don’t care a damn for what the enemy does out of his sight, but it scares me like hell!”

Grant’s refusal to be paralyzed by imagining what the enemy was doing owed to an epiphany early in the war when he was leading a regiment for the first time, in pursuit of Confederate Colonel Thomas Harris in Missouri.

“As we approached the brow of the hill from which it was expected we could see Harris’ camp, and possibly find his men ready formed to meet us, my heart kept getting higher and higher until it felt to me as though it was in my throat,” Grant recalls in his memoirs.

But when he had the good fortune to find the camp abandoned, Grant’s “heart resumed its place.” He learned the vital lesson that his adversary “had been as much afraid of me as I had been of him... From that event to the close of the war, I never experienced trepidation upon confronting an enemy, though I always felt more or less anxiety.”

In April 1862, during the bloody two-day Battle of Shiloh, Grant did not share his colleagues’ bleak view. Sherman was demoralized by the first day’s fighting, while Don Carlos Buell, who arrived with reinforcements in the midst of the battle, advised retreat. Grant refused: “The distant rear of an army engaged in battle is not the best place from which to judge correctly what is going on in front,” he asserts in his memoirs.

By the next day, he continues, “We had now become the attacking party. The enemy was driven back all day, as we had been the day before, until finally he beat a precipitate retreat.”

In May 1864, after fighting to a costly stalemate in his first battle with Robert E. Lee, at the Wilderness, in Virginia, Grant surprised and delighted the Union Army of the Potomac by not retreating, as they had done so many times before under different commanders.

“Most of us thought…that the next day we should recross the river,” a captain in a Massachusetts regiment remembered, “but when the order came, ‘By the left flank, march!’ we found that Grant was not made that way, and we must continue the fight.”

Sherman likewise celebrated Grant’s decision: “When Grant cried ‘Forward!’ after the battle of the Wilderness, I said: ‘This is the grandest act of his life; now I feel that the rebellion will be crushed.’ I wrote him, saying it was a bold order to give, and...it showed the mettle of which he was made.”

What Sherman called Grant’s “simple faith in success” proved infectious. His confidence and determination made others believe in themselves as well: “when you have completed your best preparations, you go into battle without hesitation...no doubts, no reserve,” Sherman wrote to Grant. “I tell you that it was this that made us act with confidence. I knew wherever I was that you thought of me, and if I got in a tight place you would come—if alive.”

But Grant was no mystic, nor was he reckless. His confidence was rooted in an unswerving sense of purpose, an unflappable nature, an ability to delegate responsibility as opposed to micromanaging, and knowledge gained by cool and careful observation over the years.

In the Mexican War, he studied two commanders in action: Winfield Scott and Zachary Taylor, whose nicknames—“Old Fuss and Feathers” and “Old Rough and Ready”—encapsulate their antithetical styles. From Taylor, who always “put his meaning so plainly there could be no mistaking it,” Grant learned the importance of clear and direct communication.

It was in Mexico, while serving as regimental quartermaster and involving himself in as many battles as he could, that Grant had learned the decidedly unromantic aspects of war: the ingenuity required to feed and supply an army, the hazards of poor camp sanitation, the value of different kinds of expertise and the unequivocal brutality of combat.

In the last year of the Civil War, as casualties mounted and the horrors of trench warfare accumulated in the Battles of Cold Harbor and Petersburg, Grant remained fixed in his purpose to destroy Lee’s army.

In addition to being a gifted writer, Grant was an expert listener—“at his best,” one staff officer suggested, in “sudden emergencies.” Faced with a new situation, as he was on arriving in the besieged city of Chattanooga in late 1863, Grant sat “as silent as the sphinx” while officers delivered their reports, according to an eyewitness. Then, after firing “whole volleys of questions,” he proceeded to write out a series of dispatches.

The biographer William McFeely explains the significance of this episode: Grant’s “orders and telegrams...demonstrated a grasp of the whole of the Western Theater of the war. From the disjointed reports he had been given, he put together a coherent picture of the terrain of an area new to him, and of the vast confused array of men who contended for it.”

Grant’s memory for terrain was photographic. One staff officer observed that after one hard look at a map, “he could follow its features without referring to it again. Besides, he possessed an almost intuitive knowledge of topography, and never became confused as to the points of the compass.” This gift was complemented by superb horsemanship, which allowed Grant to see for himself as much of the battlefield as possible.

In the Eastern Theater, which he studied for only eight weeks, Grant revealed a thorough grasp of the strategic situation. He decided to leave executive command of the Army of the Potomac to George G. Meade in order to give himself time to manage an extensive area of operations stretching from New England to New Mexico, from Minnesota to Mississippi.

“Wherever Lee goes,” he ordered Meade, “there you will go also.” Keeping Lee’s army engaged, Grant unleashed Philip Sheridan’s cavalry on the Shenandoah Valley, the breadbasket of the Confederacy, and freed Sherman to march through the South destroying railroads, supplies—and morale.

Yet none of this would have been possible had Grant not also comprehended the war’s larger political context and harmonized his efforts on the battlefield with the aims of the Lincoln administration. As the latter enlarged from preservation of the Union to the freeing of enslaved persons in the Confederacy with the Emancipation Proclamation of 1863, Grant’s policies and vision likewise evolved.

His way of prosecuting the war and securing the peace revealed a sure understanding of the war’s political stakes—and of the fact that the South’s best hope of victory was to sap the political will of the North by prolonging the war.

For Grant, who as a young man had fought in the Mexican War, a conflict in which he did not believe, the Civil War was a war of principle. At the conclusion of his memoirs, he sums it up with his customary lucidity when he describes the Confederate cause as “one of the worst for which a people ever fought, and one for which there was the least excuse.”

This essay does not reflect the official policy or position of the Department of the Army, the Department of Defense or the U.S. Government.